Monday, August 30, 2010

Things You Remember Around Ponds

But let’s back up a day.

That Thursday afternoon, after we arrived at the cabin and unloaded the car, AW and I sat out on the beach and relaxed a bit. The cabin sits on the point of an esker which is joined to the “mainland” by a small 1-lane bridge just a short walk away. The sun was out, the air warm, and we gazed across the lake as the Twins played in the water and Bird Whisperer went out to explore. After a short while, he returned.

BW: Hey Dad, there’s a lady fishing on the bridge who says she knew you when you were a kid.

Me: What’s her name?

BW: A-----.

Me: Does she have blond hair?

BW: Yes.

One of the fringe benefits of living 2,500 miles from where you grew up is that there is a whole class of awkward encounters, or more properly re-encounters, to which you are almost never subject. Living in Utah I never unexpectedly run into anyone who ever sentenced me to detention, or with whom I tried unsuccessfully to make out*, or who saw me wearing bell-bottoms, working at the White Hen Pantry or dancing to KC and the Sunshine Band. The people in this category of encounter include former teachers, marching band directors, friends-of-parents, schoolyard bullies, newspaper-route-customers-who-never-tipped, and of course, former girlfriends.

*Barring one awkward early-dating incident with AW.

Walking toward the bridge I saw a blond-haired woman helping a young boy to fish. Seeing me approach, she stood up and smiled, and I was strangely relieved to see that, more than 2 decades since I’d last seen her, she was instantly recognizable, her form and weight apparently the same. Never before having run into someone 27 years after we’d dated, I wasn’t quite sure of what to say, so I blurted out the first thing to come into my head: “I didn’t know you fished.”

The human body is strange on so many levels. It’s this amazing machine that can do all sorts of things, comprised of all these complex parts. And the weirdest part is probably the brain. Think about it: everything else is in your body is doing something- moving, bearing loads, fighting germs, digesting food, transporting oxygen and nutrients, secreting stuff- all kinds of things. And then there’s the brain. It’s this huge organ you carry around all day up high on this big stalk, encased in this bony shell, which uses an inordinate portion of the calories consumed by the human body, and it doesn’t do anything.

Oh, I know it “does” stuff. But it’s like this giant clump of interconnected cells that are firing electrical signals all over the place, pretty much all day long. For sure, some of these actions make a lot of sense (Hey, my finger is in the spokes, it hurts, I better send a signal to my arm muscle to pull it out…) but others (I’ve always felt that Major Nelson’s eventual marriage to Jeannie was vaguely misogynistic...) seem awfully trivial for the expense and general overhead that the brain requires.

Of all the weird stuff the brain does, I’m not sure any is weirder than memory. If I tell you to think about your mother, an “image” of your mom pretty much instantly “comes into” your “mind.” Probably you “see” her face, maybe you “hear” her voice, or maybe even recall her scent. How’s that? A moment ago you didn’t see her face, and now you do. Where was it? Where and how was it stored and how did your mind suddenly produce it at my suggestion? Isn’t that bizarre?

And I can do the same for lots of other memories. If I ask you to think of the day you graduated high school/college, or the day you started your first job, or the day the Challenger blew up, or 9/11, each of those “commands” will trigger not just a picture, but a “scene.” Chances are you can tell me where you were, what you were doing, and who you were with at the time. And the recall of some/many of those memories may actually change your emotional state, making you happy, sad or wistful. But you weren’t happy, sad or wistful a moment ago. How did that happen? Isn’t that the weirdest thing ever??

A----- and I both laughed and embraced. As we did the side of my face brushed against her hair, and my arms briefly wrapped around her shoulders/upper back. I caught a brief, slight, scent- a perfume, a body wash, a deodorant, a powder?*- I don’t know what, but it was somehow vaguely, reminiscently similar to her scent in the early 1980’s. A scent I hadn’t smelled, remembered or even remembered remembering for more than a quarter-century, and the sudden recollection of it triggered a whole other level of images, memories of actually being with/around her**.

*The myriad products with which women treat, anoint and enscent*** their persons will ever remain a mystery to me.

**I don’t know how I smelled to her. But given that I’d spent 3 ½ hours in the car and then gone for a quick swim, my guess is that if anything it was sort of a low-grade BO doused with pond-water. Which, come to think of it, was probably how I usually smelled most of the time in summers in the early 1980’s.

If memory is weird, then trigger-memories are extra-weird. You may smell or see something, or hear an old song, and then suddenly recall detailed memories you hadn’t thought of in decades. My sister- let’s call her Elizabeth- who has a great memory, will often trigger such memories when we’re together. She’ll say, “Remember that time when we…” and then suddenly I do remember that time, long ago, in vivid detail, even though I hadn’t even thought of it in decades. That memory was sitting somewhere in my brain in many cases for the majority of my life, completely un-recalled, until just now.

The brain is frustrating because although we know a lot about it, we still can’t “put it all together.” We understand the basic elements, and we know a fair amount about the overall structure, but we don’t understand exactly how they fit together to do something like form, store and recall memories*. At a cellular level, researchers understand pretty well how the machinery functions. Your brain is composed overwhelmingly of 2 types of cells: neurons, or “nerve cells”, and ganglia, which support the neurons and handle much of the “care & feeding” of the brain. The neurons are where the action is, connected to each other and transmitting signals from one to the other like crazy

*Brain Researcher David Linden calls this gap “the Middle Thing”.

Neurons connect to one another via long, tendril-like extensions called dendrites and axons. Signals are sent out on axons and received on dendrites. The axon of one neuron is connected to the dendrite of the next by a synapse, which a teeny-weeny gap, about 1/500th the width of a hair*, filled with the saltwater fluid in which the brain is immersed/bathed/inundated.

The neurons maintain a voltage differential relative to the surrounding saltwater solution of about -70 millivolts, the result of a relative excess of potassium ions inside the neuron and relative excess of sodium ions in the fluid outside. When a signal is generated, ions are rapidly exchanged across the surface of the neuron, generating a voltage spike of about +50 millivolts, which travels rapidly* down the axon toward the next synaptic cleft.

*Well actually not all that rapidly, as we’ll see in a moment…

When the spike reaches the synapse, the end of the axon releases one or more of a series of different chemicals, jointly classified as neurotransmitters, which transmit the signal to the end of the dendrite of the next neuron on the other side of the cleft, and so on and so on. I’m leaving out a bunch of details, but that’s the gist of how signals are transmitted around the brain. This hardware has been around for a long time- at least as long as jellyfish have been around- and it’s how nerve cells work in pretty much every living thing that has a nervous system. So while our brains are certainly more impressive than that of a jellyfish*, they’re constructed out of the same parts, which aren’t particularly impressive. Nerve signals are transmitted at no more (and usually less) than a rather leisurely 120 m/s, and they’re remarkably unreliable in getting to their destination; some significant portion of signals just don’t get through. The brain works because it’s hugely redundantly “over-wired”. Compared with copper wire, neurons are slow and unreliable.

*Which actually has no brain…

A----- and I stood and caught up while her son cast his line from the bridge. After a few minutes the Twins ambled up, curious, and were soon chatting with her son while he showed them how to cast. As I spoke with her I noticed little differences from the A----- I remembered- a few lines near the eyes, and hair that revealed subtle highlights closer up*. I remembered her eyes, and how one day I’d swear they were blue, and then the next they’d be green**. I remembered, way back, mentioning it to her and her laughing it off. I’d wonder sometimes if they somehow caught and flashed back the gleam of the sky or the water, or if they conveyed some mood or secret in her. Or me.

*Because practically no woman has blonde hair after 40, as I mentioned in this post. Yes, I know this is a complete non-news item to female readers, but I never knew it till I was over 40.

**No, she didn’t wear tinted contacts, she just had/has sort of in-betweeny-green/blue eyes. And then some days they’d look kind of gray.

At a macro-level, researchers also know a fair amount about brain function, and most of what they learned they’ve discovered from damage, whether accidental- through a number of fascinating Phineas Gage-type incidents- or deliberate, as in the case of test-subject monkeys and rats. Just as we carry the legacy of our ancestors at a micro/neuron level, we also do so at the macro/structural level. A lizard has a brain that seems sort of simple compared to ours. A rat has a brain that’s more complicated, and can figure out more stuff, but is still structurally simpler than ours. A chimpanzee has a brain that’s even more sophisticated than the rat’s, can do all sorts of cool stuff, and is pretty much like ours, except not as big.

But structurally a rat’s brain is more or less the stuff of a lizard’s brain, plus a bunch of other stuff. Because a rat’s brain wasn’t just designed from scratch, but rather evolved out an earlier, simpler reptilian brain. A chimpanzee’s brain- or our brain- is more or less the lizard stuff, plus the rat stuff, plus some other stuff, and that structural legacy, combined with the crappy jellyfish wiring, makes up the huge, over-wired, high-maintenance brains we have today.

Different portions of the brain (diagram above, not mine) do different things. For example there’s a part in the back of your brain that handles visual processing. We know this because if this area is damaged you can actually be blinded, even though your eyes are just fine. There are other regions which are linked to hearing, or sense of smell, or various subconscious/half-conscious functions (pumping blood, breathing). In the case of memory an important role seems to be played by a small structure on the underside called the hippocampus.

Extra Detail: Strangely, people who suffer from this type of brain-damage-blindness may still “see” after a fashion. Even though they swear they can’t see anything, such persons seem to have a better-than-random chance of locating/picking up objects or ducking/avoiding objects thrown at them. One hypothesis is that in so doing they’re somehow utilizing another more ancient part of the brain that may have been associated with vision in the ancestral/reptilian brain. The visual processing portion of our brains is an area that doesn’t exist in reptiles, but that ancestral reptilian processing hardware might possibly be intact enough in us to provide some basic function.

Tangent: A while back I did a couple of posts on vision in birds. Later I did a post on the evolution of avian intelligence, where I talked a bit about the structure of bird brains. But I never made the obvious link between the two topics until now. When I previously tried to imagine avian vision, I pictured vision sort of like my own, except with new/ unimaginable colors, greater clarity, binocular-like foveal power and perhaps even an overlay of features I couldn’t see at all, such as magnetic fields. But now this image seems almost naïve. So much of “vision” happens in the brain, and bird brains have nothing like our visual processing hardware, but probably(?) have a completely different processing center which evolved along a completely different path from reptiles. Avian vision may well be as alien to us as the sonic “vision” of bats.

The hippocampus is the part that allows you to make and store new memories, and the way we know this is because people who experience severe damage to the hippocampus are unable to make new memories, even though they remember old stuff. So while the person remembers their mother or childhood friend or where they were when the Challenger exploded just fine, if they were to meet you today, and then you returned to see them again tomorrow, they’d have no idea who you were.

Extra Detail: Interestingly, this seems to be true for declarative memories, but not for non-declarative memories. Declarative memories are specific facts or events. “Twin A is allergic to eggs…” is a declarative memory. Non-declarative memories are things like skills, such as ice-skating, or playing the ukulele. A person with a trashed hippocampus can be taught to ice-skate (even if they have to be reintroduced to their instructor over and over again…)

But hippocampus damage reveals something else about memories: they move over time. A person with a damaged hippocampus not only is unable to form new memories, but also loses recent memories, where “recent” is anywhere from 1 to 4 years. Memories, like wine, age, and as they do so are moved elsewhere.

So where do they go? I remember way back in junior high school (I think) seeing a film in science class where a researcher is doing some kind of brain surgery on a patient who is conscious. (Do you remember this? No seriously, I’m not messing with you; I think most American kids in public schools at roughly that grade level in the 70’s or early 80’s saw this…) In the film, the researcher touches different parts of the brain- the outer brain, the neocortex- with an electrical probe, and as he does so the patient suddenly recalls specific old memories in incredible vivid detail. The takeaway was that memories are stored, sort of like sensurround movies in specific locations in the neocortex.

That film- like the film in which flat worms learned knew tasks by eating mashed-up flatworms who already knew the task- was largely bogus*. The content behind the brain-surgery-electro-stim-memory film came out of experiments in the 1930’s by a Canadian neurosurgeon named Wilder Penfield**. Penfield’s electro-stim experiments did produce vivid recollections, but only in about 5% of the cases. The rest of the time such stimulation produced various reactions, including hallucinations.

*They were almost certainly following the slime trails of the previous flatworms.

**To be clear, the oversimplified claims of memory-locations were not Penfield’s doing. Penfield’s research made huge accomplishments in mapping the functional areas of the brain.

It’s not known for sure where long-term memories are stored, but the most commonly-accepted idea nowadays is that the components of memories are stored in areas having to do with specific senses. In other words, images are stored in the visual-processing area, smells in the olfactory-processing area, etc. And when you recall a memory, your brain somehow “grabs” these components, which must somehow be linked or “tagged” and brings them to “mind” in a cohesive “scene.” That’s the thinking, anyway.

All About My Neurological Disorder

Extra-Big-Side-Note-Tangent: This one is a bit lengthy, and goes rather far afield, but I hope you’ll indulge me as it has personal significance.

This “tagging” or linking- if that is in fact what is going on- may sometimes manifest itself in odd ways. Some number of people, possibly as many as 1 in 20*, exhibit a pattern in memories which suggests a non-standard linkage, or possible “cross-wiring” of the specific mnemonic elements that comprise a given memory. In the condition known as synesthesia, the recall or triggering of a memory or even a sensory input automatically, consistently and involuntarily triggers another memory, image or sensation. For example, a synesthete may always see the number 6 as green. Or they may smell a particular food when they see a bridge. Or they may feel a tingle in their hand when they hear a particular piece or type of music.

*But possibly far fewer. More on this in a moment.

There are over 60 documented (and probably many, many undocumented) forms of synesthesia. One of best known is most common is Grapheme -> Color Synesthesia, where the subject perceives numbers or letters as having specific, consistent colors. Another common form is Sound -> Color Synesthesia, where the subject associates specific sounds- musical tones, animal sounds, whatever- with specific colors. A much rarer form is Lexical -> Gustatory Synesthesia, in which the subject experiences actual tastes in association with specific spoken words*.

*This one sounds kind of cool. If you knew the triggers for your favorite foods, could you enjoy fat-free delicacies all day long just be listening to a played-back recording of those words?

Synesthesia has fascinated me since I first heard of it a few years back, because while I never considered myself a synesthete, I’ve always knew that I had an unusually visual way of thinking of numbers and dates. It wasn’t until researching this post that I realized that I am in fact synesthetic. The specific form of synesthesia from which I “suffer”(!) is another common form, Number -> Form Synesthesia.

In Number -> Form Synesthesia, a visual “map” of numbers comes to mind whenever that person thinks of numbers. For as long as I can remember, this is exactly what happens with me, though I’ve always thought of the numbers as having a “path” more than a “map”. Here’s how I “see” the numbers 1 through 20:

You’ll note the obvious clock influence between 6 and 12. I see this when I count, when I perform arithmetic, and when I learn/recite numbers in a foreign language. Interestingly, I don’t think of the hours of the day in this form, but in accordance with a standard 12-hour clock. When I extend the path/map up to 100, it looks like this:

The 0 – 100 path/map maintains its form at higher orders of magnitude. 0- 1000 follows the same map. When I think of numbers in the thousands- say income for example- I think of the same map from 0 to 100,000 and then the same map again from 0 to 1,000,000 when thinking of income in the low to mid six figures. Negative numbers follow a similar path/map, but with the direction, aspect and flow a bit different. I also see this path/map- especially with the negative number component- when thinking about time in terms (specifically) of years. Here’s how I see recorded Western history:

Here’s how I see biological/geological history:

Here’s my temporally “in-between” path/map of human history over the last 200,000 years:

Interestingly, I don’t see the months of the year, nor the days of the month, along this map. But I see them along another path/map. Here’s what the months of the year look like to me:

The days in this map are on the same path/map; I see days of (specifically) the month as “zooms”. But I see the days of the week on a different path/map, specifically like this:

This one, like the clock part of my number path/map, I suspect has a clear origin. I have a memory (quite possibly wrong) of seeing a days-of-the-week chart similar to this path/map on the TV show “Romper Room” when I was around 5 years old, with Saturday and Sunday both bigger and “higher”, just as in my path/map.

I emphasize here that these aren’t just typical Watcher-graphics I cooked up for this post. I’ve always seen numbers and dates on these paths, for as long as I can remember. In many cases Number ->Form synesthetes report color associations with map-elements, but that’s not the case with me; my path/maps have no connection with color.

Numbers around synesthesia are way squishy. Estimates have ranged from 1 in 20 to 1 in 200,000 people. Older research indicated a much higher prevalence among women (6-to-1!) but more recent studies suggest that perhaps the female participants in earlier surveys were simply more forthcoming. A similar, maybe-possible correlation has been suggested for left-handedness.* For a while it was suspected that synesthesia was linked to the X chromosome, but this idea seems to have fallen by the wayside of late. More recent research hints at a possible link to chromosome #2 in an area associated with autism and epilepsy.

*I am right-handed.

Getting back to me, it’s been hypothesized that Number -> Form Synesthesia is the result of some kind of cross-wiring in an area of the brain called the parietal lobe (diagram left, not mine), a region that handles both numeric and spatial processing. N->F Synesthesia is interesting because it hints at spatial-numeric links that be unconsciously present in everyone, but which are unusually “visible” in N->F synesthetes.

A----- and I caught up on the happenings of old friends around the lake: who did what, lived where, etc. Over the years we’d been kept somewhat abreast of each other’s lives through our parents. She knew that I bike-raced; I knew that she’d recently been divorced. When the conversation came around to families, I made what seemed the obligatory consolatory remark, mentioning that I’d heard she and her husband had split up, and was sorry to hear it.

“Don’t be,” she answered, a bit too quickly. “It’s a good thing.” Her swift response hinted at the sting of recent unpleasantness, and we moved on to other subjects..

There’s another part of the brain, just slightly below/in front of the hippocampus, called the amygdala (see the first diagram). This component, which seems to be part of the ancient reptilian core structure, appears to be associated with some of the most “primitive”, basic emotions, such as fear and anger, and is suspected to be involved with the retention of important memories. When an event happens to us that’s particular painful or fearful or otherwise traumatic, the amygdala seems to be triggered, as if it’s somehow “stamping” the event, or underlining it, marking it as important. This may be why we all remember where we were and what were doing on September 11, 2001, and yet likely have no idea what we were doing on October 4, 2002. Because on September 11 we were afraid, we were angry and our memory of that day was “stamped” by the amygdala.

Tangent: We all know how the “sting” of bad memories such as a death or a break-up seems to fade a bit after time. Bad memories are still bad, but many, many years later they just don’t, well, “hurt” quite as much as they did when they were fresh*. I wonder if somehow, as memories are transferred from the hippocampus to their eventual homes in the neocortex, if not quite all of the amygdala-“stamping” is included in the transfer…

*My own divorce probably falls into this category. Part of that is probably because my life turned so, well, great**. But memories of those times seem somehow muted, or removed, and when I think back on those days, it’s almost like thinking about some stuff that happened to somebody else. (Which, in a strict materialistic sense, maybe it was.)

**That sounds cocky, but it’s not meant to be. If you have a loving family, good health, good friends, enough money to get along decently and live in a beautiful place to boot, well I call that a great life. The rest is up to you.

In a previous post I blogged a bit about the mystery of self. If we are the stuff that comprises our brains, and over a period of years that stuff is gradually replaced by new stuff, then ultimately, are any of our long-term neocortical memories really “ours”? Maybe old memories seem distant and strange in a way because they’re not really ours, but rather a storybook of sorts, a tale of our past, ever-changing selves, which shaped and made possible the self we are today.

Maybe, as A----- and I talked on the bridge, it was two strangers speaking. Strangers who each carried around a storybook of tales in their heads, and whose storybooks overlapped for a while and shared a chapter many years ago. Like new acquaintances who discover they’ve enjoyed the same book, it was fun to reminisce and catch up.

We think of the people closest to us- our siblings, our spouses, our parents, as somehow always being the same age they were when we got to know them. AW will always be around 30, Brother Phil will always be a brainy 10 or 11 year-old, and my father will always be in his late 30’s, as he was when together we camped up by the lake the summer he built the cabin. But with old acquaintances we once knew well though haven’t seen in years, there’s a sort of disconnect between the “them” we remember and the “them” we see now. As I talked with A----- on the bridge, I saw two people before me- the 45 year old woman, and the 18 year-old girl, different and yet the same, somehow overlaid together as both a person and a memory at the same time. Looking at her, I caught a glimpse of her storybook, and mine, in her green eyes. I mean blue.

Note About Sources: My primary source for this post was David Linden’s The Accidental Mind, which was one of my 2 very enjoyable vacation reads*. Additional info on synesthesia came from Wikipedia, as well as this helpful site. Additional info on neurons and their electrochemical function came from this site and this site.

Very fascinating post today, Watcher. I've always been fascinated by the brain, the mind and the Self-- especially other people's sense of Self, how they see the world around them and themselves from inside their minds.

And thanks, Kristin, for the link to the NPR story! Very interesting stuff.

I've tried several times (often prompted by your posts) to imagine how the world would be perceived with different senses (like bat sonar) or a more dominant sense (like a dog's nose). Or wit ha different sense of time - slow like a turtle, fast like a swallow, long like a Sequoia, short like most insects. It's unsettling, yet also alluring. I can see why reincarnation is an interesting idea.

Enel- Unfortunately, there's no "Rainman"-style upside; I can't count cards or signal aliens or see dead people or anything.

KKris- I think I was secretly hoping someone would comment and say, "Oh yeah, I see numbers too..." Ah well, the lack of such an affirming comment confirms my freakishness. At least now when I behave inappropriately I have an excuse. You know, neurological disorder and all...